1. Field of the Invention
The present invention relates generally to a method for solids entrainment. More specifically, the invention is a method for entrainment and removal of solids from a wellbore through the use of a relatively low density gel.
2. Description of the Prior Art
During typical fracturing operations a variety of particulate or solid materials, such as sand, are introduced to the wellbore. Producing wells can also introduce fines and other solids that may ultimately reduce production by restricting the flow of oil. In both these cases the solids must be cleaned or removed from the wellbore. In favorable cases water can be used to remove the solids, but this requires high flow rates with annular velocities in the order of 150 ft/min. It is usual to use viscosified solutions of polymers, and particularly biopolymers, such as hydroxyethyl cellulose (HEC), xanthan or guar and rely on the reduced settling rate in the fluid to clean the hole.
Because the settling rate is not zero, the result of such operations typically result in the spread of solids over a longer portion of the wellbore.